The present invention relates to a portable data collection device including a two dimensional photosensor array imaging assembly and, more particularly, to a portable data collection device having a two dimensional photosensor array imaging assembly selectively actuatable to read a bar code dataform and record an image of an item of interest and further having an optic assembly with a variable focusing module to change a best focus distance of the optic assembly.
Portable data collection devices are widely used in manufacturing, service and package delivery industries to perform a variety of on-site data collection activities. Such portable data collection devices often include integrated bar code dataform readers adapted to read bar code dataforms affixed to products, product packaging and/or containers in warehouses, retail stores, shipping terminals, etc. for inventory control, tracking, production control and expediting, quality assurance and other purposes. Various bar code dataform readers have been proposed for portable data collection devices including laser scanners and one dimensional (ID) charge coupled device (CCD) imaging assemblies, both of which are capable of reading ID bar code dataforms, that is, bar codes consisting of a single row of contrasting black bars and white spaces of varying widths. Both of these readers are also capable of reading a xe2x80x9cstackedxe2x80x9d two dimensional (2D) bar code dataforms such as PDF417, which has row indicator patterns utilized by the reader for vertical synchronization.
A two dimensional (2D) imaging based dataform reader has been proposed in U.S. application Ser. No. 08/544,618, filed Oct. 18, 1995 and entitled xe2x80x9cExtended Working Range Dataform Reader Including Fuzzy Logic Image Control Circuitryxe2x80x9d, now issued as U.S. Pat. No. 5,702,059 on Dec. 30, 1997. The 2D dataform reader disclosed in application Ser. No. 08/544,618, includes an imaging assembly having a two dimensional array of photosensors or photodiodes adapted to read 2D bar code dataforms (e.g., PDF-417, Supercode, etc.) with vertical synchronization row indicator patterns as well as matrix dataforms (e.g., MaxiCode, Data Matrix, Code 1, etc.) which do not include vertical synchronization patterns. The photosensors correspond to image pixels of a captured image frame and the terms xe2x80x9cphotosensorsxe2x80x9d and xe2x80x9cpixelsxe2x80x9d will be used interchangeably. The 2D dataform reader disclosed in U.S. Pat. No. 5,703,059 utilizes an open loop feedback control system including fuzzy logic circuitry to determine proper exposure time and gain parameters for a camera assembly. U.S. Pat. No. 5,702,059 is incorporated in its entirety herein by reference.
While using a portable data collection device to sequentially read bar code dataforms affixed to products or containers in a production facility, warehouse or retail store, an operator may come upon an item which is damaged, incomplete, mislabeled, in the wrong location, etc. In such a event, it would be desirable for the operator to make a note of the problem item so that appropriate corrective action may be taken by supervisory personnel. However, requiring the operator to make a handwritten notation on a clipboard or input information concerning the item using a keyboard or keypad of the portable data collection device is both time consuming and error prone. What is needed is a portable data collection device having a 2D imaging assembly that can be actuated to read bar code dataforms by depressing a trigger and, when a problem item is found, the imaging assembly can be actuated with a separate trigger to record an image of the problem item. This would enable xe2x80x9cinformationxe2x80x9d, that is, an image of the problem item, to be recorded without seriously interrupting the normal course of the operator""s work. Additionally, it would be desirable to transmit the recorded image of the problem item to appropriate supervisory personnel so that appropriate corrective action may be taken. In certain instances, it may be sufficient to record a single frame of the image of a problem item, while in other cases, for example, if the item is larger than a field of view or target area of the imaging assembly, it may be necessary to record a continuous video image of the problem item to permit the operator to record a complete view of the item. It would also be desirable to provide an audio capture module to simultaneously capture the operator""s voice, enabling the operator to provide further identification and/or commentary on the problem item to aid supervisory personnel in locating the item and taking appropriate corrective action.
Additionally, what is needed is a portable data collection device including an illumination assembly and a viewing assembly to assist the operator in properly aiming and positioning the portable data collection device with respect to a target object such that the target object is within a target area of the imaging assembly. A size of a target area of the imaging assembly is defined by a field of view of the imaging assembly and a distance between the imaging assembly and the target object. The target object may be a dataform to be read or an item to be imaged. Preferably the illumination assembly will include targeting optics which will project a xe2x80x9ccrosshairxe2x80x9d shaped targeting beam of visible light corresponding to the field of view of the imaging assembly to aid an operator in aiming the device at the target object.
A viewing assembly would permit the operator to visualize the target area and the target object. Visualizing the target area of the image assembly would facilitate proper alignment of the target area and the target object thus insuring that the device is properly aimed. Further, visualizing the imaging target area and the target object would aid the operator in positioning the device relative to the target object such that the target object is encompassed within an outer perimeter of the target area.
Furthermore, in package delivery applications, upon delivery of a package, the delivery person typically uses a portable data collection device to read a bar code dataform affixed to the delivered package. Normally, the delivery person also obtains a signature of the person receiving the package. Typically, the signature of the person receiving the package is on a sheet of paper that must be filed with the package delivery records or on a signature capture digitizer pad so that the signature may electronically filed.
What is needed is a portable data collection device having a 2D imaging assembly that can be actuated to read a bar code dataform by depressing one trigger and can be actuated by a separate trigger, or applications software, to record an image of a signature of a person receiving a package so that the signature can be filed electronically.
As an alternative to using one trigger to read a bar code dataform and using the second trigger to image an adjacent signature block with a recipient""s signature included therein a single trigger could be used to image and decode a dataform and capture an image of the recipient""s signature. If the dataform includes encoded data regarding the position of the signature block with respect to the dataform, output data could include decoded dataform data and data representing the portion of the captured image corresponding to the signature block area. What is needed is a portable data collection device that can be actuated by a single trigger to capture an image of a bar code dataform and an adjacent signature block, decode the bar code dataform, determine the position of the signature block, and output a compressed digitized representation of the portion of the image comprising the signature block for subsequent downloading to a remote device.
What is also needed is an optic assembly for focusing an image of the target area onto a two dimensional photosensor array wherein the optic assembly includes a focusing module to permit the best focusing distance of the optic assembly to be changed by the operator manually or changed automatically in response to a signal representative of the sharpness of an image of a target area.
In accordance with this invention, a portable data collection device is provided that includes a two dimensional (2D) photosensor array imaging assembly selectively actuatable for reading bar code dataforms (bar code dataform reading mode) and recording an image of an item in the imaging assembly""s target area (imaging mode). A size of the target area is dependent on a field of view of the imaging assembly and a distance between the imaging assembly and a target object, the object being either a dataform to be read or an item to be imaged. The portable data collection device includes two trigger switches, a first trigger actuatable for reading a bar code dataform and a second trigger actuatable for recording an image of an item in the target area. In a radio embodiment of the portable data collection device of the present invention, a radio module is provided for transmitting an output signal to a remote device. In a batch embodiment of the portable data collection device of the present invention, an output signal is coupled to a terminal processing board for further processing and storage.
The imaging assembly of the portable data collection device of the present invention further includes control and selection circuitry which receives input signals from an operator of the portable data collection device and determines and formats an appropriate output signal. The output signal may include data from a decoded dataform imaged in a captured image frame, a compressed representation of a captured image, an uncompressed representation of a captured image, or a combination of these. If the desired output signal is decoded dataform data, the selection circuitry will utilize image processing and decoding circuitry to decode the dataform.
Alternately, if the desired output signal is to represent an image of a field of view of a camera assembly of the imaging assembly, the selection circuitry may output the entire frame of image data from the buffer memory or, if appropriate, invoke a compression module to compress the image to reduce the quantity of data to be transmitted by a radio module of the portable data collection device to a remote device or to be output to a terminal processing board of the portable data collection device.
As discussed, the portable data collection device of the present invention includes two manually activated trigger switches for controlling the selection circuitry to select between a imaging capture mode and a dataform decoding mode. A first trigger switch, the dataform decoding trigger, institutes the dataform decoding mode and signals the selection circuitry to output a decoded representation of a dataform in a captured image frame. The second trigger switch, the imaging trigger, institutes the imaging mode and has two operating embodiments. In the first operating embodiment of the imaging mode, depressing the imaging trigger results in the imaging assembly capturing one frame of the field of view or target area of the camera assembly. In the second operating embodiment of the imaging mode, depressing the imaging trigger results in the imaging assembly continuously capturing successive frames as long as the trigger is depressed.
In a third operating embodiment of the portable data collection device of the present invention, activation of the dataform reading trigger will result in both decoded data and at least a portion of the captured image frame being output. This embodiment would advantageously be employed in a situation where a dataform is associated with, for example, a signature block in proximity to the dataform wherein the dataform includes encoded data setting forth the position of the signature block with respect to some predetermined location on the dataform. When the dataform decoding trigger is actuated, an image of the dataform and associated signature block is captured. The dataform is decoded and the decoded data is analyzed by the selection circuitry to determine the location of the signature block. The output signal includes both the decoded data and an image of the signature block.
Advantageously, the portable data collection device of the present invention includes a voice capture module which captures and digitizes sound received through a microphone mounted on the device during actuation of the second trigger. This feature enables an operator to xe2x80x9cattachxe2x80x9d a verbal message to the captured image. The digitized signal representing the captured sound portion is processed by a voice compression module prior to output to the radio module or the terminal processing board.
The imaging assembly includes a board camera assembly having a photosensor array assembly including a two dimensional (2D) array of photosensors or pixels and a control and decoder board. The control and decoder board includes decoding circuitry, image compression circuitry, control and selection circuitry, serial output circuitry, exposure parameter control circuitry and image buffering circuitry including signal processing circuitry and a frame buffer memory. The signal processing circuitry includes synchronization extractor circuitry and analog to digital (A/D) converter circuitry for converting a composite video signal generated by the board camera assembly to digital image data. The decoding circuitry includes a decoder for decoding 1D and 2D bar code dataforms. The exposure parameter control circuitry includes fuzzy logic control circuitry for controlling the frame exposure period and gain adjustment of the board camera assembly.
The imaging assembly further includes an illumination assembly for illuminating a target item in the imaging assembly target area and an optic assembly for focusing reflected light from the target area upon the 2D array of photosensors of the photosensor array assembly.
The optic assembly includes a plurality of lens positioned to the front of the 2D photosensor array for focusing reflected light from the target area onto the photosensor array. A shroud supports the optic assembly and shrouds ambient illumination from the photosensor array. The optic assembly also includes a variable focusing module for varying the best focus distance of the optic assembly. The focusing module of the present invention permits clear imaging of an object as near as 5.5 inches (140 mm.) from a front lens of the optic assembly to as far as 36 inches (915 mm.) from the optic assembly, that is, the focusing module provides for a best focus range of 5.5 inches to 36 inches.
The board camera assembly includes the 2D photosensor array, exposure period control circuitry and gain control circuitry mounted on a printed circuit board. The illumination assembly includes an array of LED illuminators for uniformly illuminating the target area and two targeting LED illuminators for generating a cross hair illumination intensity pattern for aiming the portable data collection device appropriately. In a first embodiment of the illumination assembly, a lens array is disclosed having a first targeting optics which generates a first crosshair illumination pattern and a second targeting optics generating a second crosshair illumination pattern, the first and second illumination patterns coinciding at distance corresponding to a minimum value of the best focus range of the optic assembly, that is, at a distance approximately 5.5 inches (140 mm.) from the front lens of the optic assembly. In a second embodiment, a lens array is disclosed having a first targeting optics which generates a half frame and a crosshair illumination pattern and a second targeting optics which generates a complementary half frame and crosshair illumination pattern. At the minimum value best focus position, the first and second illumination patterns combine to generate a full frame and single crosshair illumination pattern.
The device further includes a viewing assembly to further aid in aiming and positioning the portable data collection device with respect to a target object. A pivoting member is manually pivotable into an upright position in a line of vision of the operator. The pivoting member defines an aperture. The operator holds the device at a fixed distance with respect to his or her viewing eye and looks through the aperture to view the target object. The aperture is sized such that when an operator viewing eye is approximately 56 millimeters (mm.) from the pivoting member, a view seen through the aperture is substantially equivalent to the target area of the imaging assembly. Thus, the operator may advantageously use the aperture both for properly aiming the device at the target object and for moving the device closer to or further away from the target object so that the target object is large as possible but still is imaged within a perimeter of the target area. When the operator does not desire to use the viewing assembly, the pivoting member is folded down out of the operator""s line of vision and out of harm""s way.
The portable data collection device of the present invention includes pistol-grip shaped housing enclosing circuitry of the device. An angled snout extending from a grip portion of the housing includes an opening through which a portion of the illumination assembly and optic assembly extend. A finger operated trigger is provided on a target facing surface of the housing. The trigger is depressed by an operator to actuate the imaging assembly to read a bar code dataform in the target area. A push button actuator extends through an opening of the housing spaced apart from the trigger. The push button actuator is located so as to be depressible by the operator""s thumb as the housing is cradled in the operator""s hand. Depressing the push button actuator actuates the imaging assembly to capture an image of the target area. A slider extends through a slotted opening the in the housing and is operatively connected to the focusing module. By changing position of the slider, a thickness of an optic through which reflected light passes is altered and the best focusing position of the optic assembly is correspondingly changed. In an alternate embodiment of the focusing module, image analysis circuitry is provided which analyzes gray scale values corresponding to a captured image frame and automatically changes the thickness of the focusing module optic to achieve the image of a target area.
The aforementioned and other aspects of the present invention are described in more detail in the detailed description and accompanying drawings which follow.